Automatic telephone system



C. W. KECKLEB. AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED MAR.2I, |91?.

Patented Feb. 8, 1921.

HMM/2 ffy 'v4/flu UNITED STATES PATENT OFFICE.

CHARLES W. lKEGKLER, OF NEWARK, NEVI JERSEY, ASSGNOR TO WESTERN ELECTRICCOMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORIPORATION 0F NEW YORK.

AUTOMATIC TELEHONE SYSTEM.

Specification of Letters Patent.

Patented Feb. 8, 1921.

Application filed March 21, 1917. Serial No. 156,314.

Y 10 all 'w hom t may concern Be it known that I, Ci-mnnns W. Klienten,a citizen ot the United States, residing at Newark in the county otEssex and State of New Jersey, have invented certain new and usefulImprovements in Automatic Telephone Systems, of which the following is afull, clear, concise, and exact description.

This invention relates to substation circuits for use with substationsending devices tor automatic telephone exchange systems.

Heretofore in automatic telephone systems ,in which the callingsubscriber operates a calling device or impulse sending mechanism tocontrol the operation ot selecting apparatus, it has been necessary thatthe subscriber remove his receiverfrom the switchhoolr before operatinghis calling device, so as to allow a line finder or an equivalent switchto operate at the central office to extend the line circuit to theselecting apparatus which is to be controlled by the first series ofimpulses.

The object of this invention is the provision ci a substation circuitarrangement for use with a calling device whereby the line circuit isclosed to start the line finder or an equivalent switch at the centralcnice as soon as the calling device is moved from its normal position.An oit-normal contact is closed by the initial movement of the dial ofthe calling device which completes a bridge across the line conductorsand allows the line' finder to operate before the impulses aretransmitted by the return movement of dial to its normal position.

This invention may be more readily understood by referenceto theaccompanying drawings, in which Figure l shows a preferred substationarrangement embodying this invention; and Fig. 2 shows a modication ofthe circuit arrangement shown in Fig. l.

Beferring'to Fig. 1 of the drawings, 1 designates the usual ringer inseries with a condenser 2 in the normal circuit of the line conductors 3and 4. A telephone transmitter 5 and a primary winding 7 of an inductioncoil 6 are included in a normally open bridge of the line conductors,and are arranged to be brought intocircuit upon the removal of thetelephone receiver 9 from its switchhook 10. The receiver 9 and thesecondary coil 8 of the induction coil 6 are also arranged to be broughtinto circuit upon the removal. of the receiver.

Associated with the substation circuit is a calling device 11 having adial 12 rotatable about the axis 13 and provided with the teeth Ahcllcrank lever 15, pivoted at 1G is located in operative relation tothe dial 12. One arm of the lever is engaged by the teeth oi the dial12, and the other arm is eiigaged by the contact arm 17, which alsoengages the contact 18. The contact arm il? is connected to contact 24by a conductor 26. Two conductors, 19 and 20, eX- tend from theinduction coil leads, as shown, and terminate in the contact 21 and thecontact arm respectively.` An arm 23 is fastened to the wheel. 12 and isremovable therewith. Contacts 24., 21 and contact arm 22 constitute anoff-normal switch, and the closing of this switch when the callingdevice moves from normal places a bridge across the line conductors 3and 4l, and also places a shunt around lthe receiver 9, which shunt ismaintained until after the required number of impulses is sent and thecalling device returns to normal. y

rThe operation is as follows, it being assumed that the calling partydoes not move his receiver until after he has started operating hiscalling device to send out the lirst set of impulses. Only so much of .1telephone system has been shown as is thought necessary for a completeunderstanding of thc invention. The system hercin disclosed is similarto that shown in Patent No. 1,231,013, issued June 26, 1917, to C. L.Goodrum. As a preliminary to Vthe sending of the impulses, the dial 12is moved in the direction of the arrow a required di,.- tancecorresponding to the number ot impulses to be sent, after which it isreturned to normal by the action of a spring (not shown). As soon as thedial leaves its normal position, a circuit is closed :tor the startmagnet 30 of the line finder from grounded battery, right-hand windingof relay 30, line conductor at, conductor 27, contact 18, contact arm17, conductor 26, contact 24:, conductor 19, primary coil 7, lineconductor 3, lett-hand winding of relay 30 to ground. Relay 30 becomesenergized and starts the line switch operating to extend the lineconductors 3 and 4 to a first selector. As soon as the calling line isfound cut-off relay 111 is energized and opens the circuit of relay 30.

In the return of the dial l2 to its normal position, the teeth la engagethe bell-crank lever l5, thereby making and breaking, at contacts 17 and18, the bridge across the line circuit which by this time extends to the`first selector and completes a circuit for a line relay Ll0 oi thisselector. rlhe relay 40 is thereby energized and denergized a number ortimes Acorresponding to the number of impulses transmitted, to move theselector to the desired group or' trunks. rlhe relay E30 will bedenergized at this time, because as soon as the line finder linds theVcalling line the cut-ofi relay fl-.l is energized to open the circuit ofrelay 30.

The moving of the dial from normal also places a short circuit,conductor 19, contacts 2l` and 22 and conduct-or 20, about the receiver.rThe switch contact 2Q is arranged to Vengage contact 2l before thecircuit through contact 24 is completed. lWhen this circuit is completedthrough the primary coil 7 to start the line finder, and later made andbroken to transmit impulses to the selector switch, the current which isinduced in the secondary by these current changes does not-affect thereceiver' because of the shunt around it. Therefore, when the subscriber removes his receiver during the operation ot the calling device,he does not receive adisagreeable click in his receiver each time acircuit change is produced.

Upon the dialreaching its normal posi-V tion, arm engages contact arm22, thereby Aopening the shunt for the circuit of receiver Y), but thereis no effect produced in the receiver, since at this time there is asteady flow of current through the primary coil :trom ground at theselector, conductor 3,

contact arm l0, transmitter contact arm the primary coil i oit theinduction coil asv in Fig. l, as the calling device in this circuitarrangement short-circults all oi. the substation apparatus as soon asit leaves its `normal position. The disadvantage et this circuitarrangement shown in Fig. 2 is that the calling subscriber receives-aclick in his receiver at the end of each dial movement, when current isrestablished through the primary of the induction coil.

V'Jhat is claimed is: 4

l. ln a substation circuit for an automatic telephone system, a callingdevice having normally closed impulse springs, a normally open linecircuit, a hook switch, a normally pen short-circuit around the hookswitch,

and means operated by the initial movement oi' said calling device forclosing said short-circuit and closingsaid line circuit through saidimpulse springs.

ln a substation circuit for an automatic exchange system, a callingdevice having' impulse springs, sets of ofhnormal springs controlled bysaid calling device, a line circuit includingA said impulse springs andone set of said off-normal springs, and a short circuit around thetelephone receiver controlled by another set of said oli-normal springs.

3. ln a substation circuit for automatic telephone systems, a callingdevice having normally closed impulse springs, a normally open linecircuit, a receiver, a normally open short circuit around said receiver,and means operated by the initial movement of said calling device forfirst closing said short circuit and then closing said line circuitthrough said impulse springs.`

a. ln a substation circuit for automatic telephone systems, a callingdevice having impulse springs and sets of onormal springs, a linecircuit including said impulse springs and one set of otfnormal springs,a telephone receiver, and a short circuit around said receiver includinganother set ot ofi-normal springs.

ln a substation circuit for automatic telephone systems, a callingdevice having impulse, springs and sets or oli-normal springs, a linecircuit including said impulse springs and one set of off-normalsprings, a telephone receiver, a short circuit around said receiverincluding another set of off-normal springs, and means controlled by themovement of the calling device for closing the short` circuit in advanceof closing the line circuit.

In Witness whereof, l hereunto subscribe' my naine this 20th day ofMarch A. D., 1917.

' CHARLES KECKLER.l

